package com.kexun.common.utils;

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import java.io.UnsupportedEncodingException;
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class Sha256 {
    /**
     * 利用java原生的摘要实现SHA256加密
     *
     * @param str 加密后的报文
     * @return
     */
    public static String getSHA256StrJava(String str) {
        MessageDigest messageDigest;
        String encodeStr = "";
        try {
            messageDigest = MessageDigest.getInstance("SHA-256");
            messageDigest.update(str.getBytes("UTF-8"));
            encodeStr = byte2Hex(messageDigest.digest());
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
        return encodeStr;
    }

    /**
     * 将byte转为16进制
     *
     * @param bytes
     * @return
     */
    public static String byte2Hex(byte[] bytes) {
        StringBuffer stringBuffer = new StringBuffer();
        String temp = null;
        for (int i = 0; i < bytes.length; i++) {
            temp = Integer.toHexString(bytes[i] & 0xFF);
            if (temp.length() == 1) {
                //1得到一位的进行补0操作
                stringBuffer.append("0");
            }
            stringBuffer.append(temp);
        }
        return stringBuffer.toString();
    }

    /**
     * 创建签名
     *
     * @param message
     * @param secret
     * @return
     */
    public static String createSign(String message, String secret) {
        String sign = "";
        byte[] keyByte = secret.getBytes(StandardCharsets.UTF_8);
        byte[] messageBytes = message.getBytes(StandardCharsets.UTF_8);
        try {
            Mac hmacSha256 = Mac.getInstance("HmacSHA256");
            hmacSha256.init(new SecretKeySpec(keyByte, 0, keyByte.length, "HmacSHA256"));
            byte[] hmacSha256Bytes = hmacSha256.doFinal(messageBytes);
            sign = byte2Hex(hmacSha256Bytes).replaceAll("-", "").toLowerCase();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return sign;
    }

}
